The cellular electrophysiologic properties of a new antiarrkythmic substance,tetrahydropalmatine(TRP),were studied in isolated canine cardiac Purldnje fibers and ventricular muscles.In lharkinjc fibers,the shortening ...The cellular electrophysiologic properties of a new antiarrkythmic substance,tetrahydropalmatine(TRP),were studied in isolated canine cardiac Purldnje fibers and ventricular muscles.In lharkinjc fibers,the shortening of APD50 produced by THP was concentration dependent,APD90was shortened only at higher concentrations of THP,APA and Vmax were decreased by increasing theTHP concentration to 100 and 300 μmol/L. In Veutricular muscles,THP,at higher Concentration,shortened APDs,and APD90 The reductions of Vmax and APA were significant only at highest concentration,300 μmol/L,ERP was relatively prolonged in both Purldnje fibers and ventricular muscles.These studies suggest that THP may inhibit Ca2+ and Na+ movement across the membrane of myocardlal cells.展开更多
Long-duration ventricular fibrillation (LDVF) often occurring out-of-hospital has been presented several minutes before electrical shocks. It is important to understand the mechanism by which LDVF is maintained and de...Long-duration ventricular fibrillation (LDVF) often occurring out-of-hospital has been presented several minutes before electrical shocks. It is important to understand the mechanism by which LDVF is maintained and defibrillated. Purkinje fibers (PFs) have been demonstrated to play a key role in the onset of certain types of ventricular fibrillation. In this review, we discuss the electrophysiological difference between PFs and working myocardium, and the role of the PFs in the maintenance and termination of LDVF.展开更多
The theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje f...The theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describethe long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domainbut nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram maysuddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonbly the phenomena that patients with cardiac diseases might suddenly die without warning.展开更多
文摘The cellular electrophysiologic properties of a new antiarrkythmic substance,tetrahydropalmatine(TRP),were studied in isolated canine cardiac Purldnje fibers and ventricular muscles.In lharkinjc fibers,the shortening of APD50 produced by THP was concentration dependent,APD90was shortened only at higher concentrations of THP,APA and Vmax were decreased by increasing theTHP concentration to 100 and 300 μmol/L. In Veutricular muscles,THP,at higher Concentration,shortened APDs,and APD90 The reductions of Vmax and APA were significant only at highest concentration,300 μmol/L,ERP was relatively prolonged in both Purldnje fibers and ventricular muscles.These studies suggest that THP may inhibit Ca2+ and Na+ movement across the membrane of myocardlal cells.
基金Supported by National Natural Science Foundation of China (81000081,81070266)
文摘Long-duration ventricular fibrillation (LDVF) often occurring out-of-hospital has been presented several minutes before electrical shocks. It is important to understand the mechanism by which LDVF is maintained and defibrillated. Purkinje fibers (PFs) have been demonstrated to play a key role in the onset of certain types of ventricular fibrillation. In this review, we discuss the electrophysiological difference between PFs and working myocardium, and the role of the PFs in the maintenance and termination of LDVF.
文摘The theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describethe long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domainbut nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram maysuddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonbly the phenomena that patients with cardiac diseases might suddenly die without warning.
